title: A population-based description of atrial fibrillation in the emergency department, 2002 to 2010.
abstract: OBJECTIVE
  We aimed to describe the demographics, care, and outcomes of patients with atrial fibrillation in the emergency department (ED), as well as temporal changes over time.
  
  
  METHODS
  In this retrospective cohort study, we used a province-wide database to identify all adult patients who were treated in a nonpediatric ED in the province of Ontario with a primary diagnosis of atrial fibrillation, April 2002 to March 2010. We determined the frequency and rate of ED visits and assessed patient demographics, ED care, and outcomes, both overall and by year.
  
  
  RESULTS
  During the 8-year study period, 113,786 patients made 143,003 ED visits for atrial fibrillation, accounting for 0.5% of all ED visits. The annual number of ED visits increased from 15,931 to 20,168 (29.4%; 95% confidence interval [CI] 28.7% to 30.1%) between 2002 and 2010, whereas the crude rate increased from 172 per 100,000 to 195 per 100,000 persons. Median age was 72.0 years (Interquartile range 61.0 to 80.0 years) and 50.8% were women, which did not change significantly during the study period. The percentage of index ED visits with a physician billing for cardioversion increased from 6.3% (95% CI 5.9% to 6.7%) to 11.8% (95% CI 11.3% to 12.3%). Although the percentage of patients with a CHADS2 score greater than or equal to 2 increased from 49.3% (95% CI 48.4% to 50.2%) to 53.6% (95% CI 52.9% to 54.4%) and high-acuity ED triage scores increased from 41.1% (95% CI 40.2% to 42.0%) to 62.5% (95% CI 61.7% to 63.2%), hospital admissions decreased from 48.1% (95% CI 47.3% to 49.0%) to 38.4% (95% CI 37.6% to 39.2%). Thirty-day mortality was 3.3% (95% CI 3.2% to 3.4%) and showed a slight downward trend during the study period (P=.05), whereas subsequent hospitalizations within 30 days for atrial fibrillation or stroke (2.8%; 95% CI 2.7% to 2.9%) and repeated ED visits (7.3%; 95% CI 7.1% to 7.4%) remained unchanged.
  
  
  CONCLUSIONS
  The number of ED visits for atrial fibrillation increased markedly during an 8-year period. Although it appears that slightly higher-risk patients are being treated in the province's EDs, fewer patients are being admitted to the hospital, and mortality rates have not increased.
authors.affiliation: Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada; Division of Emergency Medicine, Department of Medicine, University of Toronto, Toronto, Ontario, Canada; Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada. Electronic address: clare.atzema@ices.on.ca.
authors.forename: Clare L
authors.initials: CL
authors.lastname: Atzema
authors.forename: Peter C
authors.initials: PC
authors.lastname: Austin
authors.forename: Eli
authors.initials: E
authors.lastname: Miller
authors.forename: Alice S
authors.initials: AS
authors.lastname: Chong
authors.forename: Lingsong
authors.initials: L
authors.lastname: Yun
authors.forename: Paul
authors.initials: P
authors.lastname: Dorian
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000453:epidemiology* / Q000628:therapy; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D009864:Ontario / Q000453:epidemiology; D012189:Retrospective Studies; D012720:Severity of Illness Index; D012737:Sex Factors; D014218:Triage / Q000706:statistics & numerical data